The present application is related to a vehicle inspection or measurement system configured to utilize non-contact optical sensors to acquire images and measurement data associated with a vehicle wheel assembly mounted on a vehicle moving through a field of view, and in particular, to methods for measuring dimensions of observed wheel assembly components from the acquired images and measurement data.
Vehicle wheel alignment systems have utilized a variety of techniques for non-contact measurement of stationary vehicle wheel assembly parameters, from which vehicle wheel alignment angles can be determined. For example, by utilizing multiple displacement measurement sensors, distances between known sensor locations and locations on a stationary vehicle wheel assembly can be measured. Processing the acquired measurements from displacement sensors observing wheel assemblies on opposite sides of an axle can identify planes parallel to the wheel assembly surfaces, from which representations of total toe and camber angles can be determined. In other configurations, two-dimensional images of a stationary vehicle wheel assembly are acquired, and image processing algorithms utilized to identify geometric features such as the wheel rim edge, from which a perspective analysis can be performed to determine estimates of vehicle wheel assembly spatial position and orientation. Alternatively, structured light patterns, such as multiple laser lines, or colored stripes, are projected onto the stationary wheel assembly surfaces and observed by an imaging system. Deviations in the projected pattern are analyzed to generate representations of the illuminated surfaces, from which the vehicle wheel assembly spatial position and orientation is estimated. In general, these systems require the vehicle to remain stationary relative to the sensors during the measurement acquisition procedure, but some non-contact measurement systems require either the wheel assembly or the sensors be rotated about a fixed axis of rotation during the measurement acquisition procedure.
Few non-contact measurement systems can acquire measurements as a vehicle wheel assembly is both rotated and translated past the sensors, i.e., as the vehicle on which it is mounted is rolled or driven past the sensors. For example, laser displacement sensors can be used to measure a distance between a fixed sensor and various points on vehicle wheel assemblies on opposite sides of a vehicle as the vehicle is driven at a slow speed between a pair of sensors. The system acquires measurement data along horizontal slices of the individual wheel assemblies, from which approximations of the wheel spatial orientations can be derived. Laser displacement systems are highly influenced by the speed at which the vehicle travels between the sensors, the angle (straightness) of vehicle travel relative to the sensor observation axis, suspension movement, and any changes in steering of the vehicle as it passes between sensors. Measurements acquired from a moving vehicle are useful to provide a vehicle service quick check or audit inspection, capable of identifying vehicles which may be in need of a further, more precise, alignment inspection and/or adjustment.
In order to fully evaluate the needs of a vehicle during a quick check or audit inspection, it is beneficial to identify the vehicle by make, model, year, installed options, or other identifying features in order to create a vehicle inspection record, retrieve the appropriate vehicle specifications, or identify outstanding recalls, etc. from a database. If a need for tire replacement is noted, such as by acquiring measurements of tire tread depth as the vehicle moves through the quick check or audit inspection system, it would be beneficial to determine dimensions of the individual wheel assemblies installed on the vehicle, consisting of rims and tires, in order to recommend a suitable replacement tire having a size which matches the tires currently installed on the vehicle. Identification of wheel assembly dimensions can further aid in identifying a specific manufacturer trim level associated with the vehicle which may not otherwise be identifiable from a decoded VIN number.
Accordingly, it would be advantageous to provide a vehicle quick check or audit inspection system, which acquires measurement data and images from a vehicle moving through an inspection lane, with the ability to determine dimensions associated with the wheel assemblies of the vehicle as it moves past a sensor field of view. It would be further advantageous to provide a vehicle quick check or audit inspection system with the capability of identifying wheel rim bead seat diameters for individual wheel assemblies of a passing vehicle, of identifying tire sizes for tires installed on individual wheel assemblies of a passing vehicle, and/or the capability of utilizing vehicle wheel assembly dimensions to identify a manufacturer trim level of a passing vehicle.